The present invention relates to devices for administering, injecting, infusing, delivering or dispensing a substance, and to methods of making and using such devices. More particularly, it relates to an administering device for a liquid drug which can be a liquid formulation which contains FSH or an FSH variant. For the purposes of the present invention, not only liquids in the narrower sense but also pasty and gelatinous drugs are to be regarded as liquid drugs, as long as such drugs can be conveyed in a way comparable to a liquid. In some embodiments, an administering device in accordance with the present invention is an injection device for administering a substance by an infusing injection needle, e.g. for a subcutaneous injection, but it can in principle also be an injection device for needle-less administering or an inhalation device. In some embodiments, an injection device in accordance with the present invention takes the form of a so-called injection pen.
Modern injection pens enable a drug to be precisely dosed, even individually or personally by a patient. The increased flexibility due to the freely selectable dosage enables the device to be used in therapies in which the patients administer a drug to themselves—so-called self-administering. Self-administering in particular demands a high level of operational security and operational convenience. The devices should inherently prevent operational errors. One source of error is air trapped in the drug reservoir. If this air is not removed before administering, there is a danger that the drug to be administered will not be administered in the dosage set but rather together with the trapped air in accordance with the dosage set. The drug reservoir is therefore vented before administering, a process which is generally known as “priming”. In the majority of devices, priming is left to the instinct of the patient, who for this purpose sets a small dosage on a dosing member, holds the device with the needle pointing up, and delivers the priming volume set into the air by activating the device. Other devices, for example a device known from EP 0 927 058 A1, are specially equipped with priming mechanisms which may entail a highly complex design and therefore significantly increased costs.
Because of the need to reduce costs, more and more therapies are being given over to self-administering. One example is stimulating the ovaries and consequently, by fertilizing the stimulated egg cells, pregnancy using hormone treatment. Thus, for example, EP 1 188 444 B1 describes liquid formulations based on FSH (follicle stimulating hormone) and FSH variants. To also be able to administer FSH and FSH variants by self-administering, the liquid formulation—the drug—is preserved. A preservative is added to the active agent FSH or an FSH variant—in a liquid solution. If unpreserved, there would be a danger of the drug containing the FSH or an FSH variant becoming contaminated, such that it would have to be administered within a few hours, and optimally immediately, after contact with air. In most cases, therefore, the drug is dispensed in a preserved form in larger containers, from which the patients can charge their administering device, i.e. fill its reservoir with the preserved drug. Alternatively, the patient is provided with two containers, one with an unpreserved formulation and the other with the preservative, such that the patient can personally mix the preserved drug and store it for a longer period of time in its then preserved state. In addition to the preserving effect, the preservative has, if any, a negative effect on the stability of the active agent (FSH or FSH variants) and also increases the price of the prepared, preserved drug. Charging or mixing the administering device from a larger, sterilely sealed container which contains a preserved or unpreserved formulation is awkward and requires that the dosage to be administered be charged exactly.